Diagnostic value of quantification of circulating free DNA for gall bladder cancer using a chemiluminescence DNA biosensor system based on DNA G-quadruplex/ hemin enzyme

•In this study, we designed a novel detection system to detect DNA based on DNA G-quadruplex/hemin enzyme. It consisted of DNA probes with hemin that can form a special structure via self-assembly after paring with target DNA. The special structure containing hemin showed enzyme activity catalyzing substrates for coloration or luminescence.•Based on this chemiluminescence DNA biosensor system using DNA G-quadruplex/hemin enzyme, we designed a pair of DNA probes targeting β-actin DNA to detect circulating free DNA (cfDNA) in human serum from patients with gall bladder cancer (GBC), patients with cholecystitis, and healthy donors and calculated concentrations of cfDNA according to a standard curve.•In the serum of patients with GBC, the level of cfDNA was higher than those in the serum of patients with cholecystitis and healthy donors.•This is a convenient, economic, and promising approach to aid the diagnosis of patients with GBC via detecting serum cfDNA. Gall bladder cancer (GBC) is an insidious but rapidly progressed disease with a poor prognosis and high mortality rate. To explore a novel method for GBC diagnosis, we quantified circulating free DNA (cfDNA) in serum samples from 228 participants, including 83 patients with GBC, 75 patients with cholecystitis, and 70 healthy donors, using a chemiluminescence DNA biosensor system based on DNA G-quadruplex/hemin enzyme. We measured β-actin gene expression to evaluate serum cfDNA levels representing as chemiluminescence intensity with the addition of sufficient probes. We analyzed associations of cfDNA quantities in serum samples and corresponding pathological stages and found that the concentration of cfDNA was significantly higher in GBC group than in the healthy control and cholecystitis groups. The levels of cfDNA were significantly associated with TNM stage, lymph node involvement, metastasis, and jaundice. The ROC curves showed that the diagnostic value of chemiluminescence DNA biosensor system was nearly equivalent to that of qPCR. Our method can distinguish patients with GBC from healthy donors and patients with cholecystitis clearly; however, this method was not available to distinguish patients with cholecystitis from the healthy controls. In summary, cfDNA maybe serve as a new diagnostic and noninvasive marker for the diagnosis of GBC using chemiluminescence DNA biosensor system based on DNA G-quadruplex/hemin enzyme.